Definition of Teratoma, ovarian

Teratoma, ovarian: Also called a dermoid cyst of the
ovary, this is a bizarre tumor, usually benign, in the ovary that
typically contains a diversity of tissues including hair, teeth,
bone, thyroid, etc.

A dermoid cyst develops from a totipotential germ cell (a primary
oocyte) that is retained within the egg sac (ovary). Being
totipotential, that cell can give rise to all orders of cells
necessary to form mature tissues and often recognizable structures
such as hair, bone and sebaceous (oily) material, neural tissue
and teeth.

Dermoid cysts may occur at any age but the prime age of detection
is in the childbearing years. The average age is 30. Up to 15% of
women with ovarian teratomas have them in both ovaries. Dermoid cysts
can range in size from a centimeter (less than a
half inch) up to 45 cm (about 17 inches) in diameter.

These cysts can cause the ovary to twist (torsion) and
imperil its blood supply. The larger the
dermoid cyst, the greater the risk of rupture with spillage of the
greasy contents which can create problems with
adhesions, pain etc. Although the large majority (about 98%) of these
tumors are benign, the remaining fraction (about 2%) becomes
cancerous
(malignant).

Removal of the dermoid cyst is usually the treatment of choice.
This can be done by laparotomy (open surgery) or laparoscopy (with a
scope). Torsion (twisting) of the ovary by the cyst is an emergency
and calls for urgent surgery.